From patchwork Mon May 15 11:57:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dietmar Eggemann X-Patchwork-Id: 94113 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp6880653vqo; Mon, 15 May 2023 05:27:57 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ6OTCie3qJkf8NwsjOnC0VCoanjzDpIduEejoe5s0pdXGe8eIY4IfK4Hisk8m6d3dOnqFuj X-Received: by 2002:a05:6a20:2455:b0:104:6432:23e with SMTP id t21-20020a056a20245500b001046432023emr13305092pzc.37.1684153676873; Mon, 15 May 2023 05:27:56 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1684153676; cv=none; d=google.com; s=arc-20160816; b=F6fiLzW0VLNW1lXmLEVEVSRwMMNA28w5sLLxqFduVYlzJElJVIo0r5mKzw8Rv3sQrO w2g/DcRnHhRV9J9fPiwUfpjMNWpAhyJHIwHjPRKfgf5EH/nm6mAXTNKfsb299FnCP1Uj FkNxKBUaGDXQbUwlxhOGiqqbyyLh8PhHnBi2+P4/X+ia6XBz1v4mvIivT+SpnOqDM7YO dkukY1rfdLybkNsAqHEpw5JATN1oH9eZcM2f48rbSR2GlW7liA7gu/FAg20kotqmdDkb TNSUEi0p+EPdaI5eGT+yU0t9dKsWfaM07AjXNba/EIyjDGiPlDTE1DNK7irC/d3fh1rh pWVg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=3WcvDJgoGQBMJBZ28SHC/VD1rFLsmHgb/INoijLAmbE=; b=Fos9KYDilPS6zMDJShiLqbZSksGruIo38C9q8tFj8P9dnnMRCsqq6RQITBmciUcytG CyqqgzCAfykJMMTJpGijCDInqGOa+wIDzHuQX/NWdnvUjVY8kWebQNFsNRtgIxP75ThO lT+AUl7bgqZkz38tlCZEanpndFB1L8edPRy+P4anUyx2q/SQsQKBkkUB7GE9wwZ+vAAd J751XxUJVJAkHYunEOilrxf6IRyFzWlnlBrcLyk/9y1kZ4vW0/Sp3mTXYkoxASfc/ExJ JWpabB3FeHH1aMiISuCSy3F52+nN4mVDBlRJ3zn1rOj+q8BQ9oyik4ha/EvIKXJPyzaW oDKg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id i184-20020a6387c1000000b0052c27a0125bsi16521413pge.738.2023.05.15.05.27.41; Mon, 15 May 2023 05:27:56 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241720AbjEOMXA (ORCPT + 99 others); Mon, 15 May 2023 08:23:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49422 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240917AbjEOMW4 (ORCPT ); Mon, 15 May 2023 08:22:56 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 214FA1BD for ; Mon, 15 May 2023 05:22:55 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DC8BD4B3; Mon, 15 May 2023 04:58:37 -0700 (PDT) Received: from e125579.fritz.box (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 90CB53F7BD; Mon, 15 May 2023 04:57:51 -0700 (PDT) From: Dietmar Eggemann To: Ingo Molnar , Peter Zijlstra , Vincent Guittot Cc: Qais Yousef , Kajetan Puchalski , Morten Rasmussen , Vincent Donnefort , Quentin Perret , Abhijeet Dharmapurikar , linux-kernel@vger.kernel.org Subject: [PATCH v3 1/2] sched/fair: Refactor CPU utilization functions Date: Mon, 15 May 2023 13:57:34 +0200 Message-Id: <20230515115735.296329-2-dietmar.eggemann@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230515115735.296329-1-dietmar.eggemann@arm.com> References: <20230515115735.296329-1-dietmar.eggemann@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1765963125875176559?= X-GMAIL-MSGID: =?utf-8?q?1765963125875176559?= There is a lot of code duplication in cpu_util_next() & cpu_util_cfs(). Remove this by allowing cpu_util_next() to be called with p = NULL. Rename cpu_util_next() to cpu_util() since the '_next' suffix is no longer necessary to distinct cpu utilization related functions. Implement cpu_util_cfs(cpu) as cpu_util(cpu, p = NULL, -1). This will allow to code future related cpu util changes only in one place, namely in cpu_util(). Signed-off-by: Dietmar Eggemann Reviewed-by: Vincent Guittot --- kernel/sched/fair.c | 63 ++++++++++++++++++++++++++++++++++---------- kernel/sched/sched.h | 47 +-------------------------------- 2 files changed, 50 insertions(+), 60 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 3f8135d7c89d..9874e28d5e38 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7145,11 +7145,41 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) return target; } -/* - * Predicts what cpu_util(@cpu) would return if @p was removed from @cpu - * (@dst_cpu = -1) or migrated to @dst_cpu. - */ -static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) +/** + * cpu_util() - Estimates the amount of CPU capacity used by CFS tasks. + * @cpu: the CPU to get the utilization for + * @p: task for which the CPU utilization should be predicted or NULL + * @dst_cpu: CPU @p migrates to, -1 if @p moves from @cpu or @p == NULL + * + * The unit of the return value must be the same as the one of CPU capacity + * so that CPU utilization can be compared with CPU capacity. + * + * CPU utilization is the sum of running time of runnable tasks plus the + * recent utilization of currently non-runnable tasks on that CPU. + * It represents the amount of CPU capacity currently used by CFS tasks in + * the range [0..max CPU capacity] with max CPU capacity being the CPU + * capacity at f_max. + * + * The estimated CPU utilization is defined as the maximum between CPU + * utilization and sum of the estimated utilization of the currently + * runnable tasks on that CPU. It preserves a utilization "snapshot" of + * previously-executed tasks, which helps better deduce how busy a CPU will + * be when a long-sleeping task wakes up. The contribution to CPU utilization + * of such a task would be significantly decayed at this point of time. + * + * CPU utilization can be higher than the current CPU capacity + * (f_curr/f_max * max CPU capacity) or even the max CPU capacity because + * of rounding errors as well as task migrations or wakeups of new tasks. + * CPU utilization has to be capped to fit into the [0..max CPU capacity] + * range. Otherwise a group of CPUs (CPU0 util = 121% + CPU1 util = 80%) + * could be seen as over-utilized even though CPU1 has 20% of spare CPU + * capacity. CPU utilization is allowed to overshoot current CPU capacity + * though since this is useful for predicting the CPU capacity required + * after task migrations (scheduler-driven DVFS). + * + * Return: (Estimated) utilization for the specified CPU. + */ +static unsigned long cpu_util(int cpu, struct task_struct *p, int dst_cpu) { struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs; unsigned long util = READ_ONCE(cfs_rq->avg.util_avg); @@ -7160,9 +7190,9 @@ static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) * contribution. In all the other cases @cpu is not impacted by the * migration so its util_avg is already correct. */ - if (task_cpu(p) == cpu && dst_cpu != cpu) + if (p && task_cpu(p) == cpu && dst_cpu != cpu) lsub_positive(&util, task_util(p)); - else if (task_cpu(p) != cpu && dst_cpu == cpu) + else if (p && task_cpu(p) != cpu && dst_cpu == cpu) util += task_util(p); if (sched_feat(UTIL_EST)) { @@ -7198,7 +7228,7 @@ static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) */ if (dst_cpu == cpu) util_est += _task_util_est(p); - else if (unlikely(task_on_rq_queued(p) || current == p)) + else if (p && unlikely(task_on_rq_queued(p) || current == p)) lsub_positive(&util_est, _task_util_est(p)); util = max(util, util_est); @@ -7207,6 +7237,11 @@ static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) return min(util, capacity_orig_of(cpu)); } +unsigned long cpu_util_cfs(int cpu) +{ + return cpu_util(cpu, NULL, -1); +} + /* * cpu_util_without: compute cpu utilization without any contributions from *p * @cpu: the CPU which utilization is requested @@ -7224,9 +7259,9 @@ static unsigned long cpu_util_without(int cpu, struct task_struct *p) { /* Task has no contribution or is new */ if (cpu != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time)) - return cpu_util_cfs(cpu); + p = NULL; - return cpu_util_next(cpu, p, -1); + return cpu_util(cpu, p, -1); } /* @@ -7273,7 +7308,7 @@ static inline void eenv_task_busy_time(struct energy_env *eenv, * cpu_capacity. * * The contribution of the task @p for which we want to estimate the - * energy cost is removed (by cpu_util_next()) and must be calculated + * energy cost is removed (by cpu_util()) and must be calculated * separately (see eenv_task_busy_time). This ensures: * * - A stable PD utilization, no matter which CPU of that PD we want to place @@ -7294,7 +7329,7 @@ static inline void eenv_pd_busy_time(struct energy_env *eenv, int cpu; for_each_cpu(cpu, pd_cpus) { - unsigned long util = cpu_util_next(cpu, p, -1); + unsigned long util = cpu_util(cpu, p, -1); busy_time += effective_cpu_util(cpu, util, ENERGY_UTIL, NULL); } @@ -7318,7 +7353,7 @@ eenv_pd_max_util(struct energy_env *eenv, struct cpumask *pd_cpus, for_each_cpu(cpu, pd_cpus) { struct task_struct *tsk = (cpu == dst_cpu) ? p : NULL; - unsigned long util = cpu_util_next(cpu, p, dst_cpu); + unsigned long util = cpu_util(cpu, p, dst_cpu); unsigned long cpu_util; /* @@ -7464,7 +7499,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) if (!cpumask_test_cpu(cpu, p->cpus_ptr)) continue; - util = cpu_util_next(cpu, p, cpu); + util = cpu_util(cpu, p, cpu); cpu_cap = capacity_of(cpu); /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index ec7b3e0a2b20..f78c0f85cc76 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2946,53 +2946,8 @@ static inline unsigned long cpu_util_dl(struct rq *rq) return READ_ONCE(rq->avg_dl.util_avg); } -/** - * cpu_util_cfs() - Estimates the amount of CPU capacity used by CFS tasks. - * @cpu: the CPU to get the utilization for. - * - * The unit of the return value must be the same as the one of CPU capacity - * so that CPU utilization can be compared with CPU capacity. - * - * CPU utilization is the sum of running time of runnable tasks plus the - * recent utilization of currently non-runnable tasks on that CPU. - * It represents the amount of CPU capacity currently used by CFS tasks in - * the range [0..max CPU capacity] with max CPU capacity being the CPU - * capacity at f_max. - * - * The estimated CPU utilization is defined as the maximum between CPU - * utilization and sum of the estimated utilization of the currently - * runnable tasks on that CPU. It preserves a utilization "snapshot" of - * previously-executed tasks, which helps better deduce how busy a CPU will - * be when a long-sleeping task wakes up. The contribution to CPU utilization - * of such a task would be significantly decayed at this point of time. - * - * CPU utilization can be higher than the current CPU capacity - * (f_curr/f_max * max CPU capacity) or even the max CPU capacity because - * of rounding errors as well as task migrations or wakeups of new tasks. - * CPU utilization has to be capped to fit into the [0..max CPU capacity] - * range. Otherwise a group of CPUs (CPU0 util = 121% + CPU1 util = 80%) - * could be seen as over-utilized even though CPU1 has 20% of spare CPU - * capacity. CPU utilization is allowed to overshoot current CPU capacity - * though since this is useful for predicting the CPU capacity required - * after task migrations (scheduler-driven DVFS). - * - * Return: (Estimated) utilization for the specified CPU. - */ -static inline unsigned long cpu_util_cfs(int cpu) -{ - struct cfs_rq *cfs_rq; - unsigned long util; - - cfs_rq = &cpu_rq(cpu)->cfs; - util = READ_ONCE(cfs_rq->avg.util_avg); - if (sched_feat(UTIL_EST)) { - util = max_t(unsigned long, util, - READ_ONCE(cfs_rq->avg.util_est.enqueued)); - } - - return min(util, capacity_orig_of(cpu)); -} +extern unsigned long cpu_util_cfs(int cpu); static inline unsigned long cpu_util_rt(struct rq *rq) {